Polyhydric phenol coester stabilizers

Abstract

New polyhydric phenol coesters are disclosed of polyhydric phenols, having 2 to 3 phenolic hydroxyl groups and 1 to 3 benzenoid rings, with carbonic acid and an aliphatic dicarboxylic acid having 4 to 10 carbon atoms and optionally a thioether sulfur atom in the aliphatic chain of the dicarboxylic acid. The new coesters have molecular weights from 700 to about 10,000, preferably from 1200 to 7000, and are highly effective stabilizers for a variety of synthetic resins. Stabilizer compositions comprising a polyhydric phenol coester and a known polymer stabilizer, as well as synthetic resins stabilized with such stabilizer compositions, are also disclosed.

We claim: 
     
       1. A coester stabilizer having a molecular weight measured by a vapor pressure method between 700 and about 10,000, of at least one polyhydric phenol having 2 to 3 phenolic hydroxyl groups and 1 to 3 benzenoid rings, with carbonic acid and an aliphatic dicarboxylic acid having 4 to 10 carbon atoms and not more than one thioether sulfur atom, in which the molar proportions of carbonic acid to aliphatic dicarboxylic acid range from 19:1 to 1:19. 
     
     
       2. A coester according to claim 1 having a molecular weight between 1200 and about 7000. 
     
     
       3. A coester according to claim 1 in which the aliphatic dicarboxylic acid is succinic acid. 
     
     
       4. A coester according to claim 1 in which the aliphatic dicarboxylic acid is adipic acid. 
     
     
       5. A coester according to claim 1 in which the aliphatic dicarboxylic acid is sebacic acid. 
     
     
       6. A coester according to claim 1 in which the aliphatic dicarboxylic acid is 3,3'-thiodipropionic acid. 
     
     
       7. A coester according to claim 1 in which the polyhydric phenol has 3 benzenoid rings in the molecule. 
     
     
       8. A coester according to claim 1 in which the polyhydric phenol is an alkylidenebisphenol. 
     
     
       9. A coester according to claim 1 in which the polyhydric phenol is a bis-phenol with two benzenoid rings linked through sulfur. 
     
     
       10. A coester according to claim 1 having the formula ##STR28## in which independently at each occurrence R' is selected from the group consisting of alkyl having one to 10 carbon atoms, cycloalkyl having 5 to 10 carbon atoms, and alkylcycloalkyl having 6 to 10 carbon atoms, A is selected from the group consisting of hydrogen and ##STR29## R is selected from the group consisting of alkyl, aryl, and ##STR30## X is selected from the group consisting of --S--, ##STR31## --CH 2  SCH 2  --, O, a single bond, a divalent hydrocarbon radical, and ##STR32## where Y is a trivalent hydrocarbon radical, B is selected from the group consisting of hydrogen and ##STR33## L is 0 or 1, K is an integer from 0 to 3, m is 2 to about 20, n is an average of 0.1 to about 20, a and c are integers from 1 to 7, b is 0 or 1, and p is 0 or 1 provided that in at least one occurrence p is 1. 
     
     
       11. A stabilizer composition capable of increasing the resistance to deterioration on heating of a synthetic resin, comprising a coester according to claim 1 and at least one synthetic resin stabilizer selected from the group consisting of thiodipropionate esters, 1,2-epoxides, organic phosphites, polyhydric alcohols, polyhydric alcohol 3-alkylthiopropionates, ultraviolet absorbers, heavy metal deactivators, and barium, calcium, magnesium, nickel, strontium, tin, and zinc salts of monocarboxylic acids having 6 to 24 carbon atoms. 
     
     
       12. A stabilizer composition according to claim 11 in which the synthetic resin stabilizer is a thiodipropionate ester. 
     
     
       13. A stabilizer composition according to claim 11 in which the synthetic resin stabilizer is a 1,2-epoxide.